The guilt goes with the job.
When someone in an office job is off sick the work sits on their desk till they get back. With us teachers the 'work' is 30 kids!
However, they will be fine without you - they might even enjoy the different routine now and again and they will be all the happier to see you when you get back. No harm done!
Relax and get better!

It's all relative I suppose. There are those with weak work ethic in all fields-teachers included. I know teachers that take a day off a week due to various 'illness'.
That IS a massive strain on a school/class.

In a job where you're on the frontline facing every ailment know to man every day-it's a pretty good bet that you'll be ill now and again.

My longest stretch of health was 7 years without a sick day (plenty of colds etc in the holidays mind!). There was certainly luck in that.

Oh my goodness! Are you off long-term sick? I think the OP was talking about a sick day here or there, not a stretch of 4-5 weeks. that's an entirely different matter. How are they covering your class?